The present invention generally relates to vehicle pedal assemblies, and more particularly, to a pedal assembly, such as a brake pedal assembly, that is releasable from an operative condition upon imposition of a frontal load to an automotive vehicle.
It is generally known in the automotive vehicle design arts that it is desirable to configure components arranged within the passenger compartment of the vehicle to reduce adverse effects on the vehicle occupants when subjected to high forces such as are experienced in a collision. While many vehicle interior components facing the vehicle occupants are designed to minimize the forces during a collision impact, foot pedal assemblies, such as the brake pedal assembly which is generally positioned below the instrument panel of the vehicle in the driver""s compartment, may transfer collision caused intrusive forces to the driver""s leg. This is because in a severe frontal collision, deformation of the vehicle dash panel can cause the foot pedal assembly to move rearward toward the vehicle occupants. In addition, this rearward translation is often accompanied by some degree of rotation about a lateral axis of the mounting plane of the pedal assembly. Likewise, the reaction of the occupant in the collision can force the occupant""s legs into the foot pedal controls.
Conventional vehicle foot pedal assemblies, such as the brake pedal, clutch pedal, and acceleration pedal assemblies, are commonly assembled together in a pedal box assembly which typically is rigidly connected to the vehicle dash. Foot pedal assemblies employed with hydraulic fluid actuated systems, such as the brake pedal assembly, generally have a foot pedal pad connected to a lever and a piston push rod, with assist from a vacuum booster, that compresses a master cylinder which in turn generates hydraulic fluid pressure. As the brake pedal assembly is moved rearward toward the driver due to collision caused intrusion forces, the hydraulic resistance in the master cylinder applied against the brake pedal assembly may in some instances cause the brake pedal to inflict injury to the driver""s legs. In addition, the hydraulic resistance in the master cylinder may cause the brake pedal to damage lower extremities of the occupant due to the reaction of the occupant in a collision, independent of the dash and pedal intrusion forces.
One approach to minimizing such forces during a severe frontal collision includes structurally connecting the pedal box assembly to a cowl structure which remains relatively stable relative to the dash panel. With the pedal box assembly structurally connected to the cowl structure, relative movement can be made to cause a failure in the structure supporting the pivots of the pedal box assembly, thus allowing the pedals to move freely with little constraint following a severe frontal collision. Other approaches have included the use of mechanical connections, such as a cable, between the cowl, or some other relatively stable structure, and the pedal box. With these approaches, the deflection of the pedal assembly relative to the stable structure during a severe frontal collision is used to actively depress the pedal through the action of the aforementioned mechanical connection. However, the aforementioned approaches significantly increase the cost and complexity of the pedal box assembly, and may render the pedal assemblies inoperative following a vehicle collision.
Accordingly, there exists a need, heretofore unfulfilled, for a cost efficient device for use in a vehicle, that reduces the intrusion forces imparted to the occupant by the pedal assembly, and which reduces the forces imparted upon the occupant as the occupant reacts against the pedal assembly during a collision event.
In accordance with the teachings of the present invention, a releasable pedal system, such as a brake pedal system, for a vehicle is provided which reduces forces, such as intrusion forces, applied to the pedal system during a vehicle collision. The pedal system includes a pedal assembly that is operatively engageable by an occupant of the vehicle, and an actuator assembly for generating an amount of pressurized fluid. The releasable pedal system further includes a pressure release valve coupled in fluid communication with the pressurized fluid. The pressure release valve is operative to reduce the amount of pressurized fluid during a detected vehicle deceleration indicative of a vehicle collision. Accordingly, the releasable pedal system of the present invention advantageously reduces the forces transferred to the pedal assembly during a collision.